TFTP spawn issue

I am trying to PXE boot an OS installation media using both PXE and TFTP.
I have configured DHCP, the PXE menu file and the appropriate file
structure without issue.
However, as my client boots, on the NetBSD server I receive the
following error in /var/log/messages:
Mar 23 16:35:41 qube1 inetd[596]: tftp/udp max spawn rate
(40 in 60 seconds) exceeded; service not started
At this point it appears the TFTP daemon crashes and the OS
installation on the client fails.
I have tried changing the following line to nowait in /etc/inetd.conf,
but after a reboot, TFTP refuses to start:
tftp dgram udp wait root
/usr/libexec/tftpd tftpd -l -s /tftpboot
Anyone have any idea what I need to do to get it working? I'm running
NetBSD/cobalt 5.1.
Many thanks,
-Mark